Age Calculator
Calculate your exact age in years, months and days from your date of birth.
Updated
What is the Age Calculator?
The Age Calculator works out exactly how old you are from your date of birth.
Enter your date of birth and it instantly shows your age broken down into years, months, and days, along with your total days lived and how long until your next birthday.
Everything runs locally in your browser, so your date of birth never leaves your device.
How it works
The calculator compares your date of birth with today's date.
It subtracts the two calendar dates field by field — days, months, then years — borrowing from the previous unit whenever a value goes negative, exactly like long subtraction.
Because month lengths come from the real calendar, leap years (including February 29) are handled automatically, giving you an accurate real-world age rather than an estimate based on fixed month lengths.
Examples
Born on a leap day
Someone born on 29 Feb 2000, calculated on 1 Mar 2025, is 25 years and 1 day old.
Counting total days
A baby born on 1 Jan 2024 has lived 366 days by 1 Jan 2025 (2024 is a leap year).
Frequently asked questions
How is age calculated?
How is age calculated?
The age is calculated as the difference between today's date and your date of birth, expressed in completed years, months, and days The calculator adjusts for varying month lengths by borrowing from the previous month or year when needed, ensuring the result always matches real calendar behavior
Does it handle leap years correctly?
Does it handle leap years correctly?
Yes. The calculation uses actual calendar rules, so leap years (including February 29) are fully supported. This ensures both your age and total days lived are accurate across all years
Can I calculate my age in days?
Can I calculate my age in days?
Yes. The tool can calculate your exact age in total days, as well as the standard years, months, and days format.
Can I check my birthday countdown?
Can I check my birthday countdown?
Yes. The tool can calculate the number of days remaining until your next birthday.
Is my date of birth stored or uploaded anywhere?
Is my date of birth stored or uploaded anywhere?
No. Everything runs locally in your browser using JavaScript. Your date of birth is never sent to a server, stored, or shared
Can I calculate age between two specific dates?
Can I calculate age between two specific dates?
Yes. While the tool uses today's date by default, the underlying logic supports any reference date. This makes it useful for calculating age at a past or future point in time.
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